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A scenario is a set of related concepts pertinent to the origin of life (abiogenesis), such as the iron-sulfur world. Many alternative abiogenesis scenarios have been proposed by scientists in a variety of fields from the 1950s onwards in an attempt to explain how the complex mechanisms of life could have come into existence. These include ...
A total of 6.1 million prokaryotic genes from Bacteria and Archaea were sequenced, identifying 355 protein clusters from among 286,514 protein clusters that were probably common to the LUCA. The results suggest that the LUCA was anaerobic with a Wood–Ljungdahl (reductive Acetyl-CoA) pathway, nitrogen- and carbon-fixing, thermophilic.
Since exponential completion times are characteristic of a two-state Markov process, this observation makes kinetic proofreading one of only a few examples of biochemical processes where structural complexity results in a much simpler large-scale, phenomenological dynamics.
In trying to uncover the intermediate stages of abiogenesis, scientist Sidney W. Fox in the 1950s and 1960s, studied the spontaneous formation of peptide structures under conditions that might plausibly have existed early in Earth's history. [3]: 199–201 He demonstrated that amino acids could spontaneously form small chains called peptides ...
The LUCA probably existed at latest 3.6 billion years ago, and possibly as early as 4.3 billion years ago [2] or earlier. The nature of this point or stage of divergence remains a topic of research. All earlier forms of life preceding this divergence and all extant organisms are generally thought to share common ancestry. On the basis of a ...
A comparison of RNA (left) with DNA (right), showing the helices and nucleobases each employsThe RNA world is a hypothetical stage in the evolutionary history of life on Earth in which self-replicating RNA molecules proliferated before the evolution of DNA and proteins. [1]
According to one definition, a turn is a structural motif where the C α atoms of two residues separated by a few (usually 1 to 5) peptide bonds are close (less than 7 Å [0.70 nm]). [1] The proximity of the terminal C α atoms often correlates with formation of an inter main chain hydrogen bond between the corresponding residues. Such hydrogen ...
The dynamics of the elementary hypercycle can be modelled using the following differential equation: [3] ˙ = (+,) where =, =. In the equation above, x i is the concentration of template I i; x is the total concentration of all templates; k i is the excess production rate of template I i, which is a difference between formation f i by self-replication of the template and its degradation d i ...